We conducted an environmental education session for children on the benefits and environmental risks of detergents in order to help them understand the so-called “detergent dilemma” and the associated water pollution problem. A total of 131 fourth-grade students participated in the session. The educational program included (1) a lecture on the basic knowledge, benefits, and environmental risks associated with detergents; (2) experiments to observe the emulsification of various detergents and to evaluate their detergency; (3) experiments to develop a new detergent that has higher detergency and lower environmental impact than linear alkylbenzene sulfonates, which are the main components of synthetic detergents; and (4) a lecture disseminating more in-depth knowledge about detergents. The children who accomplished the misson of the experiments perceived that the water pollution problem could be solved, even though they conceded the detergent dilemma. We have concluded that setting a concrete target that children can achieve fosters their confidence in solving problems.